first of all, any 13" tire will be very affordable. you can probably get a set of 4 for around $100 on sale at your local tire place. anywhere from $25-40/tire is reasonable.
you won't be able to find anything approaching a high performance tire, but most in that size should afford you predictable handling and good tread life.
check out sites like
www.tirerack.com &
www.tires.com , where you can search for tires by size or model of your car.
you can find tires locally at places like firestone, goodyear, NTB, pep boys, sam's club (with membership), and other small businesses.
BF Goodrich, Goodyear, firestone/bridgestone, uniroyal/tigerpaw, futura (pep boys brand), michelin, hankook, kumho... the list of brands goes on...